UBC Theses and Dissertations
Exploratory behaviour in laboratory zebrafish : potential benefits of exploring the unknown Graham, Courtney
Zebrafish are one of the most used animals in scientific research. They are typically housed in barren conditions that greatly differ from their vegetated and fluctuating wild habitats. This disconnect has received increasing attention in recent years, particularly concerning the physical environment and the necessity of environmental enrichment. However, research investigating the psychological needs of zebrafish—a highly cognizant animal—is in its infancy. One method of addressing this gap is to investigate the use of cognitive enrichment—that is, providing a captive animal with appropriate cognitive challenge in effort to improve welfare. Therefore, the aim of this thesis was to assess the role of allowing laboratory zebrafish to engage in exploration on their behavioural responses. I provided zebrafish with an opportunity to explore novel tank space by offering them access to a previously inaccessible portion of their semi-natural home tanks, within which they had been housed for nine months. I examined their exploratory behaviour (latency and number of inspections of the novel space), anxiety behaviour (bottom-dwelling) and social behaviour (agonistic behaviour, cohesion and coordination) on the day before (baseline), the day of, the day after and two weeks after providing access to the novel area. Zebrafish were found to quickly move into the new space (on average within 9.7±7.6 seconds; mean±SD) and sustained their interest on each of the observation days (P<0.003). I found no evidence of bottom-dwelling (P>0.73), indicating that the exploration opportunity was likely not anxiety-provoking. Further, the opportunity to explore increased positive affiliative social behaviour: reducing agonistic behaviour (P=0.02), and increasing both cohesion (P=0.04) and coordination (P=0.04) relative to baseline. Considering their natural habitats would normally include such information-gain opportunities, I suggest the use of barren and stagnant laboratory conditions compromises the behavioural and psychological needs of zebrafish and reduces welfare. This thesis adds to the growing body of literature focusing on the role cognitive stimulation may play in welfare and indicates that zebrafish are good candidates for further cognitive enrichment research.
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